The present invention relates to a driven wheel assembly. More particularly, the present invention relates to a driven wheel assembly comprising an axle spindle, a rotating drive shaft, a bearing, a hub, a brake disc and a wheel rim. The invention also concerns an automotive vehicle, such as a truck, equipped with such a driven wheel assembly.
Known driven wheel assemblies for vehicles, particularly large commercial vehicles, are provided with a drive shaft, a wheel rim and a brake disc coupled in rotation to a hub which rotates with respect to a fixed axle spindle via bearings.
It is known from WO-A-2011/070387 to fasten the drive shaft, the brake disc and the wheel rim to the hub by a single set of screws which axially pass through respective fastening flanges of the drive shaft, the brake disc and the wheel rim. This solution implies that a relatively high number of parts are fastened by the same screws in the same area.
In addition, in the case where some types of wheels, which are relatively large, are mounted on the vehicle, such a solution is difficult to implement because of the reduced space available for the braking system. To allow assembly of such wheels, the disc brake must often be provided with a tubular portion whose axial length makes it less resistant to torsion.
It is desirable to propose a new driven wheel assembly which improves the mounting of the brake disc.
An aspect of the invention relates to a driven wheel assembly comprising a fixed axle spindle, a rotating drive shaft extending inside the axle spindle, a bearing, a hub, a brake disc, a wheel rim, an inner ring of the bearing being mounted on the spindle, the hub being mounted on an outer ring of the bearing, the drive shaft, the brake disc and the wheel rim being coupled in rotation with the hub, the brake disc comprising a radial friction part and a tubular portion which is fastened to the hub. This driven wheel assembly is characterized in that the brake disc is fastened to the hub by radial fastening means extending along radial directions with respect to a rotation axis of the assembly and mounted through the tubular portion of the brake disc.
Thanks to an aspect of the invention, the tubular portion of the brake disc can have a reduced length, improving its resistance to torsion and allowing mounting of brake actuator in the case of wheels having a high width.
According to further aspects of the invention which are advantageous but not compulsory, such an assembly may incorporate one or several of the following features:                The radial fastening means to fasten disc brake on the hub are located on the half length of the tubular part that is opposite to the friction part.        The radial fastening means to fasten disc brake on the hub are located on an area extending, axially between the bearing and the axial end of the hub to which is at least coupled the drive shaft.        The axial end of the tubular part opposite to the friction part is located between the bearing and the axial end of the hub and is located at distance from the axial end of the hub when measured in the direction of the rotation axis.        The radial fastening means comprise radial screws extending in radial directions with respect to the rotation axis of the assembly and mounted through the tubular portion of the brake disc.        The radial fastening means comprise radial pins inserted radially, with respect to the rotation axis X-X′, in tubular portion and in hub.        The radial pins are adjusted in first holes of the tubular portion of the brake disc and in second holes of the hub.        The radial pins are hollow, preferably they have a tubular shape, and are passed through by the radial screws that fasten the radial pins on the hub.        The hub and the tubular portion comprise friction elements adapted to increase friction between the huh and the brake disc.        The friction elements comprise a second frustoconical surface of the tubular portion of the brake disc and a corresponding first frustoconical surface of the hub, both first and second frustoconical surfaces being in contact with each other and oriented towards the rotation axis of the assembly opposite from the friction pan, and wherein the friction elements also comprise means to urge the first and the second frustoconical surfaces against each other.        The means to urge the first and second frustoconical surfaces against each other are formed by the radial screws which have a tapered head, and by a tapered surface of frustoconical holes of the tubular portion of the brake disc in which the radial screws are inserted.        The means to urge the first and the second frustoconical surfaces against each other are formed by the radial pins which have tapered outer shapes in sliding contact with corresponding tapered surfaces of first hole in order to urge the first and second frustoconical surfaces against each other when the radial pins are inserted in the hub.        The means to urge the first and second frustoconical surfaces against each other comprise wedges inserted in the tubular portion of the brake disc and in which the radial screws are inserted, and wherein a lateral surface of the wedges is inclined with respect to a longitudinal axis of the radial screws and converges towards the longitudinal axis of the radial screws opposite from a head of the radial screws, and wherein said lateral surface is in sliding, contact with a parallel surface of the tubular portion.        Each wedge protrudes radially from the tubular portion towards the rotation axis and engages a corresponding hole or groove formed on the cylindrical outside surface of the hub.        The width of the wheel rim is superior to 350 mm.        The driven wheel assembly comprises splines, polygonal surfaces or keys to couple in rotation the brake disc to the hub.        
The invention also concerns an automotive vehicle, in particular a truck, equipped with such a driven wheel assembly.